Upgrade to Lucene 10

[reckart]

Any plans upgrading to Lucene 10 for the next major version?

[jan-niestadt]

Short answer: BlackLab 4 uses Lucene 8, BlackLab 5 (current dev, should release this year) uses Lucene 9 and BlackLab 6 will use Lucene 10.

Lucene versions can generally read indexes from the previous version, so Lucene 9 can read indexes created with 8, etc. We'd like the same property to hold for major BlackLab releases if practical (it simplifies server upgrades a bit), so we'd prefer not to jump from Lucene 8 to 10 directly.

That said, Lucene 10 has a lot of performance improvements, so I'd like to upgrade to it sooner rather than later. I would be happy to be able to release v6 using Lucene 10 shortly after releasing v5. The challenge is to find the time to do it.

If you want to attempt to upgrade to Lucene 10 and do a (draft) pull request that we can work from, that would be much appreciated!